Full duplex network radio bridge with low latency and high throughput

ABSTRACT

A full duplex radio bridge using two transceivers coupled to a first packet network, one for transmitting data toward another radio bridge coupled to a second packet network, and the other for receiving data transmitted from the first packet network toward said second packet network by a transceiver of the other radio bridge. Each radio bridge is coupled to its packet network through one network port whose transmit data path is coupled to one of the transceivers, and whose receive data path is coupled to receive data from the other transceiver. An inner loop and outer loop is used. Management packets are routed to the various transceivers using the inner loop and outer loop by routing and filtering functions. Payload packets are transmitted from one packet network to the other using only the outer loop.

BACKGROUND OF THE INVENTION

Networking of high speed data over lines owned by the phone companies orother entities is expensive. Some customers want to network high speeddata and own their own infrastructure by sending the data line-of-sightby RF between antennas located at high points that are in line of sightof other antennas. This saves these customers quite a bit of money sincethey have no recurring fees, and the customers can manage and controltheir network infrastructure themselves. Since the costs are low, thereturn on investment is short.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a block diagram of a prior art radio bridge system using twohalf duplex radio transceivers at each end, each coupled to a managedrouter.

FIG. 2 is a block diagram of illustrating the loop problem.

FIG. 3 is a block diagram of one embodiment of an Ethernet radio bridgewhich solves the loop problem and which does not require either amanaged hub or commercial level router to solve this problem.

FIG. 4 shows a sequence of normal link pulses, used by 10BaseT devicesto establish link integrity.

FIG. 5 shows three trains of fast link pulses used by autonegotiatingdevices to declare their capabilities.

FIG. 6 shows how a link code word a 16 bit word is encoded in a fastlink pulse burst.

FIG. 7 shows the propagation of the Ethernet Base Control Work and LinkControl Word over the inner loop to allow activation of each link to theradio transceivers even though the each radio transceiver's Ethernetlink is unidirectional.

FIG. 8 shows a block diagram of an embodiment using a power injector topower the radio transceivers over the CAT5E wiring carrying the data upto the radio bridges.

FIGS. 9A and 9B are diagrams of two different embodiments of data pathsfor transmit, receive in the splitter circuit 134 in FIG. 8. It is thiscircuit which separates the transmit and receive pairs of the Ethernetport coupled to the radio bridges and guides the data on each pair toand from two separate half duplex radio bridge transceivers. Thecircuits of FIGS. 9A and 9B perform the segregation of the transmit andreceive signals in the CAT5E cable 109 which is necessary to make theembodiments work properly and avoid the loop condition. The circuit inFIG. 9A is for use in 10BaseT and 100BaseT Ethernet networks, and alsofunctions to segregate out the power and ground connections for aDC-to-DC converter 140. The circuit in FIG. 9B is for use in 1000BaseTand 10000BaseT Ethernet networks, and does not segregate out power andground wires because there are no power and ground wires in 1000BaseTand 10000BaseT CAT5 cables.

FIG. 10 is a diagram of the inner and outer loops and theircorresponding ports in the pair of radio bridges.

FIG. 11 is a diagram which illustrates the inner and outer loop datapaths and the various software modules which make the inner loop/outerloop routing decisions.

FIG. 12 illustrates the request path, response path and extra pathstraveled by the request packet and response packets for the scenario ofrow 1 of Table 1 where the packet source is the Ethernet port 209 andthe incoming packet from Ethernet port 209 is either a broadcast packetor a unicast management packet addressed to transceiver 201.

FIG. 13 illustrates the request path, response path and extra pathstraveled by the request packet and response packets for the scenario ofrow 2 of Table 1 where the packet source is the Ethernet port 209 andthe incoming packet from Ethernet port 209 is either a broadcast packetor a unicast management packet addressed to transceiver 203.

FIG. 14 is a diagram of how the full duplex radio bridge may be used ina multipoint-to-point or point-to-multipoint configuration.

FIG. 15 is a block diagram of two full duplex radio bridges for a10BaseT Ethernet network or 100BaseT Ethernet network where the DC-To-DCconverter 140 in FIG. 8 has been integrated onto the radio transceiverboards 114A and 116A and the splitter 134A is modified such that, inaddition to routing the transmit and receive data paths of CAT5 cable109 to Ethernet ports 120 and 118, respectively, on the radiotransceivers, it also routes the power and ground wires of CAT5 cable109 to these ports 120 and 118 where they are coupled to the on-boardDC-To-DC converters 140A and 140B. Splitter 134A also couples the innerloop data path of transceiver 114A to the inner loop data path oftransceiver 116A.

FIG. 16, comprised of FIGS. 16A, 16B, 16C and 16D, is a flowchart of thefunctionality of the transceivers of the prior art radio bridges asmodified by the addition of various routing and filtering functionality(which can be implemented either in hardware or software) to be withinthe genus of new embodiments disclosed herein.

FIG. 17 is a block diagram showing another configuration for the radiobridge where the splitting of the transmit and receive data paths of theEthernet port are done at a splitter located inside a building at thelocation of the Ethernet port and the radio boards are physicallyseparated such as up on the roof of the building.

DETAILED DESCRIPTION OF THE VARIOUS EMBODIMENTS

Prior art systems offered by Airaya and other companies such as Cisco,Proxim, Redline, etc. are all half duplex except for a full duplexproduct offered by Tranzio. Half duplex means that the radiotransceivers on each end are limited such that only one end can transmitat any particular time. Half duplex limits the data rate because all thedevices connected to the radio bridges are Ethernet devices which havefull duplex capability which is wasted.

Some attempts at full duplex have been made where two separate radiolinks are used and a commercial level gateway approximately $10,000 to$30,000 for these commercial level gateways is used at each end of theradio bridge. Such a prior art system is shown in FIG. 1. Let's call thetwo ends end #1 and end #2. At end #1 there is a first half duplexdownstream radio board having a half duplex transceiver the firsttransceiver which is transmitting data downstream. This radio bridge hasan RJ45 Ethernet port which is coupled to a first RJ45 port #1 of acommercial level router which is programmed to logically separate theupstream and downstream paths. At end #1 there is also a second halfduplex upstream radio board having a transceiver the second transceiverwhich is receiving data from end #2 simultaneously with the transmissiondownstream from end #1 by the first transceiver. The second transceiveris coupled to RJ45 port #2 of the end #1 commercial level gateway.

An identical arrangement of commercial level gateway and two half duplexradio transceivers exists at end #2.

The commercial level gateway couples the radio transceivers to thecompany's internal network. The commercial level gateway takes outgoingpackets from the internal network and sends to the transmitting radiolink the first transceiver out RJ45 port #1. The commercial levelgateway also receives incoming packets from the upstream half duplexradio link provided by the second transceiver at RJ45 port #2 and routesthem to the internal network.

To avoid a loop, the commercial level gateway is programmed to logicallyseparate the two data paths so that RJ45 port #1 is only used to sendpackets to the other side and RJ45 port #2 is only used to receivepackets from the other side. Not just any hub, switch or router can makethis logical separation. It takes a gateway which has the software andhardware which can be configured to act this way and not every hub,switch or router is. Most are not. Most hub, switches and routers havethe characteristic that when a broadcast Ethernet packet is received atany one of its RJ45 ports, that packet is broadcast out all the otherRJ45 ports of the device. Broadcast Ethernet packets are designed tofind a device which owns a specific IP address and have a MAC addresswhich has a destination MAC address which is all Fs hex. The physicallayer circuitry sees this MAC address and sends the broadcast packets upto the level 2 protocols and from there it goes to the level 3 routingprotocols to determine if the device owns the IP address specified inthe broadcast packet.

FIG. 2 is a block diagram illustrating the loop problem which wouldoccur if a hub or switch or router not having the characteristics of thecommercial level gateway were substituted for the commercial levelgateway. In FIG. 2, blocks 10 and 12 each represents a regular hub,switch or router hereafter just router with multiple RJ45 Ethernet portssuch as 14, 16, 18 and 20. Each of the routers 10 and 12 have thetypical characteristic that if a Ethernet broadcast packet arrives atone port, the same packet will be broadcast out every other port. Thisis done so that devices coupled to those ports can send the broadcastpackets up to their level 3 or higher protocol layers to determine ifthat devices owns the IP address the device which sent the broadcastpacket is looking for. Thus, if just any hub, switch or router havingthis broadcast characteristic were to be substituted for the commerciallevel gateway, a loop condition would result which would cause thenetwork to fail whenever a broadcast packet arrived.

An example will illustrate this failure mechanism. In FIG. 2, router 10has two separate RJ45 ports 14 and 16 each coupled to a different halfduplex radio transceiver 22 and 24. Transceiver 22 takes digital datareceived from port 16 in Ethernet packets and modulates that data ontoan RF carrier signal 26 which is transmitted downstream to another radiotransceiver 28 operating half duplex. Transceiver 28 converts the RFsignal back into Ethernet packets and sends them to port 18 of router12. A similar process happens for upstream Ethernet packets sent fromport 20 of router 12 to port 14 of router 10 via two half duplex radiotransceivers 30 and 24. If routers 10 and 12 are normal broadcastrouters coupled to the two half duplex radio transceiver's RJ45 ports,whenever a broadcast packet were received at RJ45 port #2 14 from end#2, it would be sent out RJ45 port #1 16 and sent to port 18 of router12 at end #2. The router 12 coupled to the two half duplex radio links28 and 30 at end #2 would then receive the broadcast packet from theradio link coupled to RJ45 port #2 18 and send it back out on RJ45 port#1 20 coupled to the upstream radio transceiver 30 and end #2 whichwould send it back to end #1. The system would then start chasing itsown tail and collapse because no payload data could be sent.

The prior art structure which solves this problem is depicted in FIG. 1and uses a commercial level gateway or managed router. The disadvantageof the prior art structure which solves this loop problem is that acommercial level gateway or managed router is needed. These areexpensive and cause latency in the system. Other worker in the art havedesigned custom, microprocessor controlled PCBs with three Ethernetconnections to mimic the same functionality of the managed router: oneRJ45 port only transmits, one RJ45 only receives and the third RJ45 isconnected to the network or upstream data source. These prior artsystems suffer the same problems as the managed router prior artsystems: extra cost and latency injected into the system while themicroprocessor on the PC board examines each packet to determine how toroute it, stores the packet in a queue in memory and transmits it later.

FIG. 3 is a block diagram of one embodiment within the genus of theinvention of an Ethernet radio bridge which solves the loop problem andwhich does not require either a managed hub or commercial level routerto solve this problem. The idea of all the embodiments disclosed hereinis to send payload data packets from one packet network to another overa radio frequency bridge without suffering from the loop problem and toallow each radio transceiver to be managed from anywhere by using aninner loop for management packets. Payload data packets are any type ofEthernet packet that has been originated on one of the packet switchednetworks coupled to a radio bridge which is to be sent to a device onanother packet switched network coupled to another radio bridge which islinked to the first radio bridge by an RF link. Management packets aredefined for purposes of this specification as either broadcast packetswhere the first 6 bytes of the desination MAC address are all hex F's orunicast packets which have a destination MAC address which belongs toone of the circuits in the transceivers of the radio bridges. Multicastpackets also exist which are supersets of broadcast packet, but they arenot relevant to the invention.

In FIG. 3, at end #1, any conventional Ethernet network element such asa hub, switch, router or computer 40 has an RJ45 Ethernet port 42 atwhich Ethernet packets are both sent and received. Every Ethernet RJ45port and it mating connector has four wires, two for transmit and twofor receive. The two transmit wires are represented by line 44. The tworeceive wires are represented by line 46.

The transmit wires 44 are connected to the receive wires of an Ethernetport 48 of a half duplex radio transceiver 50 at end #1. This radiotransceiver converts the digital data of the Ethernet packets into aradio frequency signal 52 which is transmitted to another half duplexradio transceiver at end #2. Transceiver 54 demodulates the RF carriersignal, recovers the data and packetizes it in Ethernet packets, andoutputs the recovered Ethernet packets from the two transmit wires 56 ofan RJ45 Ethernet port 58. The two transmit wires 56 of RJ45 port 58 atend #2 are coupled to the two receive wires of Ethernet port 60 of anyEthernet component 62. This Ethernet component can be any switch,router, hub, computer, etc. and has no special requirements likeEthernet component 40 at end #1 has no special requirements. TheEthernet packets received via port 60 are processed normal. If any ofthe packets are broadcast packets, they are broadcast out all otherEthernet ports of the device 62 but not out port 60 because, bydefinition, no Ethernet component transmits a broadcast packet back outthe same port upon which it was received.

Upstream packets to be sent from end #2 to end #1 are output on twotransmit wires 62 from port 60 and are received at Ethernet port 64 of ahalf duplex radio transceiver 66. There, they are converted to RFsignals 68 and transmitted to a half duplex radio transceiver 70 wherethe data is recovered, packetized and output on transmit wires 46 ofEthernet port 72. The transmit wires 46 are coupled to the receive wiresof Ethernet port 42 and the Ethernet packets are processed normally byEthernet component 40. Again, if any of the packets is a broadcastpacket, the Ethernet component 40 will broadcast them out its otherEthernet ports, but not port 42 thereby solving the looping problem.

The structure shown in FIG. 3 even without the local loops 74 and 76which will be explained more below solves the looping problem even ifthe devices 40 and 62 are not Ethernet devices but had a broadcastpacket and characteristic like Ethernet where broadcast packets receivedat one port of a switch, router or hub are broadcast out all the otherports. What solves the looping problem is the connection of one halfduplex radio bridge 50 to the two transmit wires of port 42 and theother half duplex radio bridge 70 to the two receive wires of the port42. This is true regardless of whether port 42 is an Ethernet port orsome other type of port. The structure of FIG. 3 solves the problem ofenabling full duplex communication using two radio bridges 3 evenwithout the local loops 74 and 76 even in other protocols such as RS232because the transmit wires and the receive wires of a single port areconnected to two independently operating half duplex radio bridges.

The local loop connections 74 and 76 are necessary in Ethernetapplications of the invention to enable the negotiation process tooperate properly. In Ethernet, when two Ethernet devices are coupledtogether, the devices start a negotiation to determine what each deviceis capable of and what the parameters of the Ethernet link will be. Theradio board network connection 44 is an Unshielded Twisted Pair UTP.This pair is used to communicate with the Ethernet network connection atport 42. Using this UTP connection, the two devices 40 and 50, perform anegotiation to agree on the maximum data rate and operational mode, e.g.10 Mb half duplex, 100 Mb full duplex, etc. The Ethernet 10baseT or100BaseT, 1000BaseT etc. standard requires that both ends be connectedto perform an autonegotiation and agree to a link negotiation resultbefore any data is transferred between the devices. If the negotiationdoes not occur, the link between the two devices is not established, andno data can be transferred.

Autonegotiation formerly NWay is an Ethernet procedure by which twoconnected devices choose common transmission parameters, such as speedand duplex mode. In this process, the connected devices first sharetheir capabilities as for these parameters and then choose the fastesttransmission mode they both support.

In the OSI model, autonegotiation resides in the physical layer. It wasoriginally defined in the IEEE standard 802.3u in 1995. It was placed inthe fast Ethernet part of the standard but is also backwards compatibleto 10BASE-T. However, its implementation was optional, and a part of thespecification was open to interpretation. The debatable portions of theautonegotiation specifications were eliminated by the 1998 version ofIEEE 802.3. In 1999, the negotiation protocol was significantly extendedby IEEE 802.3ab, which specified the protocol for Gigabit Ethernet,making autonegotiation mandatory for Gigabit Ethernet operation.

Autonegotiation can be used by devices that are capable of differenttransmission rates such as 10 Mbit/s and 100 Mbit/s, different duplexmodes half duplex and full duplex and/or different standards at the samespeed though in practice only one standard at each speed is widelysupported. Every device starts the negotiation by declaring itstechnology abilities, that is, its possible modes of operation. The twodevices then choose the best possible mode of operation that are sharedby the two devices, where higher speed 100 Mbit/s is preferred overlower speed 10 Mbit/s, and full duplex is preferred over half duplex atthe same speed.

Parallel detection is used when a device that is capable ofautonegotiation is connected to one that is not such as 10BaseT. Thishappens if the other device does not support autonegotiation orautonegotiation is disabled via software. In this condition, the devicethat is capable of autonegotiation can determine the speed of the otherdevice, and choose for itself the same speed. This procedure cannotdetermine the presence of full duplex, so half duplex is always assumed.

The radio boards shown in FIG. 3 are capable of autonegotiation and itis required for the embodiments disclosed herein that the devices towhich the radio boards are connected also be capable of autonegotiation.Autonegotiation is required by all embodiments within the teachings ofthe invention because the least common denominator standard for 10BaseTdevices not capable of autonegotiation is only half duplex and thisdefeats the purpose of the invention to implement full duplex.

The standard for 1000BASE-TX requires autonegotiation to be alwayspresent and enabled. Other than speed and duplex mode, autonegotiationis used to communicate the port type single port or multiport and themaster-slave parameters whether it is manually configured or not,whether the device is master or slave if this is the case, and themaster-slave seed bit otherwise.

A sequence of normal link pulses, used by 10BASE-T devices to establishlink integrity. FIG. 4 shows a sequence of normal link pulses, used by10BaseT devices to establish link integrity.

Autonegotiation is based on pulses similar to those used by 10BASE-Tdevices to detect the presence of a connection to another device. Thesepulses are sent by a device when it is not sending or receiving anydata. They are unipolar positive-only electrical pulses of a duration of100 ns, generated at intervals of 16 ms with a tolerance of 8 ms. Thesepulses were called link integrity test LIT pulses in the 10BASE-Tterminology, and are referred to as normal link pulses NLP in theautonegotiation specification.

A device detects the failure of the link which can be due either to afailure of the transmission medium or of the other device if neither apacket nor one of the pulses are received for 50-150 ms. The presence ofa valid link is signaled by the receipt of a valid packet or twoconsecutive link integrity test pulses. For this to work, devices sendlink integrity test pulses even when not receiving any.

Three trains of fast link pulses, used by autonegotiating devices todeclare their capabilities. FIG. 5 shows and example of three trains offast link pulses used by an autonegotiating device to declare itscapabilities. These pulses used as part of the autonegotiating processare still unipolar, positive-only, and of the duration of 100 ns, buteach one is replaced by a train of at most 33 pulses. Each such train iscalled a fast link pulse FLP burst. The time interval between the startof each burst is the same as the distance between normal link pulses,that is, 16 ms with a tolerance of 8 ms.

The fast link pulse burst is made as follows: there are 17 pulses atdistance 125 microseconds with tolerance of 14 microseconds. In themiddle between each set of two consecutive pulses, another pulse may ormay not be present. The presence of a pulse represents a logical 1, theabsence a logical 0. As a result, every burst represents a logical wordof 16 bits. This word is called a link code word LCW. The 17 pulses arealways present and are used as a clock, while the 16 pulses may or maynot be present and represent the actual information that is transmitted.

Every fast link pulse burst transmits a word of 16 bits known as a linkcode word. The first such word is known as a base link code word, andits bits are used as follows:

-   -   0-4: selector field: it indicates which standard is used between        IEEE 802.3 and IEEE 802.9;    -   5-12: technology ability field: this is a sequence of bits that        encode the possible modes of operations among the 100BASE-T and        10BASE-T modes;    -   13: remote fault: this is set to one when the device is        detecting a link failure;    -   14: acknowledgment: the device sets this to one to indicate the        correct reception of the base link code word from the other        party; this is detected by the reception of at least three        identical base code words;    -   15: next page: this bit is used to indicate the intention of        sending other link code words after the base link code word;

The technology ability field is composed of eight bits. For IEEE 802.3,these are as follows:

-   -   bit 0: device supports 10BASE-T    -   bit 1: device supports 10BASE-T in full duplex    -   bit 2: device supports 100BASE-TX    -   bit 3: device supports 100BASE-TX in full duplex    -   bit 4: device supports 100BASE-T4    -   bit 5: pause    -   bit 6: asymmetric pause for full duplex    -   bit 7: reserved

The acknowledgement bit is used to signal the correct reception of thebase code word. This corresponds to having received three identicalcopies of the base code word. Upon receiving these three identicalcopies, the device sends a link code word with the acknowledge bit setto one from six times to eight times.

The link code words are also called pages. The base link code word istherefore called a base page. The next page bit of the base page is 1when the device intends to send other pages, which can be used tocommunicate other abilities. These additional pages are sent only ifboth devices have sent base pages with a next page bit set to 1. Theadditional pages are still encoded as link code words using 17 clockpulses and up to 16 bit pulses.

The problem with the connection setup in FIG. 3 absent the local loop isthat the radio board 50 only receives base code words from device 40 buthas no path to send link code words back to device 40 with theacknowledgment bit set. Neither device 40 nor device 50 will light itslink light until the negotiation is successfully performed by receptionof a base code word successfully three times and transmission of a linkcode word with the acknowledge bit set. Likewise, radio board 70 cansend base code words to device 40, but cannot receive link code wordsdirectly from device 40. Some way to allow each of radio boards 50 and70 and device 40 to both receive base code words and transmit link codewords in order to successfully complete a negotiation and establishlinks on data paths 44 and 46.

To guarantee that this negotiation is performed and completessuccessfully, and a way to connect the transmit data and the receivedata to two different UTP connections of the radio bridge devices, a newconnection method was invented. The new device and network structureallows three UTP connection devices to all successfully carry out theautonegotiation even though none of the three devices can both send basecode words and receive link code words from any one of the otherdevices. Specifically, the new device and connection topology allowseach of the radio boards 50 and 70 to successfully autonegotiate withdevice 40 even though neither radio board 50 or 70 can both send basecode words to and receive link code words from the device 40.

The three UTP connections at end #1 Ethernet ports are the networkdevice 40 and each of the two radio bridge boards 50 and 70. A similarstructure exists at end #2. By connecting the UTP1-tx to UTP2-rx twowire data path 44, UTP2-tx to UTP3-rx two wire data path 74, and UTP1-rxto UTP3-tx two wire data path 46, the necessary negotiation between thethree devices is successful, allowing data to be sent in a ring betweenthe devices.

To understand this, refer to FIG. 7 which is a diagram of how the threedevices 40, 50 and 70 send base code words and link code words to eachother in a ring topology. Each device sends a base code word and gets alink code word and, as far as it is concerned, the negotiation iscomplete even though the link code word did not come from the device towhich the base code word was sent. Specifically, in FIG. 7, device 40sends a base code word represented by line 80 from the transmit wires ofits port 42 at time 1. At the same time, radio board 50 sends a basecode word represented by line 82 from the Tx wires of its port 48 to theRx wires of port 72 of radio bridge 70, and radio bridge 70 sends a basecontrol word line 84 from the Tx wires of its port 72 to the Rx wires ofport 42 of device 40. Each device, after having received three copies ofthe base control word, sends a link control word at time two out its Txwires of its respective ports. These link control words are representedby lines 86, 88 and 90. These link control words have their acknowledgebits set so when they are received by the device to which they are sent,that device thinks the link control word came from the device to whichthe base control word was sent, and the negotiation has beensuccessfully completed.

The result of this connection method, provides a data path from the upstream network connection to one of radio bridge boards and from thesecond radio board back to the up stream network connection. The 3^(rd)connection between the Tx of one radio bridge board to the Rx of theother radio bridge board defined a new communications path between allthe radio bridge devices, including the remote units. This newcommunications path is called the inner loop.

Inner Loop

The inner loop does not perform any data movement between the attachednetwork devices. By making modifications to the existing bridgingsoftware, and the use of the inner loop, all external networking devicesand other bridges, can communicate and perform configuration andmanagement on any other radio bridge devices. With communications to anyradio bridge, the network operator can configure the two radio links tofunction as required. This includes all available options defined in theWeb management and Command Line Interpreter CLI defined by theoperations manual of the prior art product made by the assignee of thisinvention.

Overall Block Diagram of an Example Embodiment Showing Actual PhysicalPartitioning of Circuitry

FIG. 8 shows a block diagram of an embodiment of two full duplex radiobridges coupled to each other and to external single network ports, eachradio bridge using a power injector to power the radio transceivers overthe CAT5E wiring carrying the data up to the radio bridges. In theembodiment shown, the radio transceivers 114 and 116 are separatecircuits from the splitter circuit 134 and the DC-To-DC converter 140and the injector circuit 106. In alternative embodiments, all thesecircuits can be a single printed circuit board, and in other alternativeembodiments, some combinations of the above listed circuits can beimplemented on one or more circuit boards so long as the functionalitydescribed below is maintained. FIG. 15 is a block diagram of two fullduplex radio bridges for a 10BaseT Ethernet network or 100BaseT Ethernetnetwork where the DC-To-DC converter 140 in FIG. 8 has been integratedonto the radio transceiver boards 114A and 116A and the splitter 134A ismodified such that, in addition to routing the transmit and receive datapaths of CAT5 cable 109 to Ethernet ports 120 and 118, respectively, onthe radio transceivers, it also routes the power and ground wires ofCAT5 cable 109 to these ports 120 and 118 where they are coupled to theon-board DC-To-DC converters 140A and 140B.

In the embodiment shown in FIG. 18, block 100 is any Ethernet hub,bridge, router, switch, computer, etc. with an RJ45 Ethernet port 102.Line 104 represents a bidirectional Ethernet link carrying signals inboth directions to and from port 102.

Injector 106 is coupled to a power supply 108 which is connected to wallAC and outputs a 48 volt DC signal on line 110. The injector 408integrates this 48 volt DC signal onto both the DC lines of the 8 wireCAT5E cable 109 going from the injector up to the radio bridge 110 whichis usually located on the roof of a building or somewhere high up toachieve line-of-sight communication with another radio bridge 112. CAT5Ecables have 8 wires: two TX, two RX, two positive DC 48 volts; and twoground. In the claims, this CAT5E cable and any other Ethernet data pathphysical format with a transmit pair and a receive pair will be referredto as an Ethernet link. In the claims, a power over Ethernet link willbe used to refer to an Ethernet link which also carries at least onewire for coupling to a +48 volts DC power supply and at least one wirefor coupling to ground. Typically a power over Ethernet link willcontain a pair of wires for coupling to a +48 VDC voltage supply, and apair of wires for coupling to ground. CAT5E Ethernet cables contain fourpairs: one transmit pair, one receive pair, one +48 VDC pair and oneground pair.

Block 110 includes the two radio transceivers 114 and 116, each of whichis a prior art radio transceiver having an Ethernet port 118 and 120, aDC input 122 and 124, a radio transceiver 126 and 128 which function toconvert the incoming payload and management (outer loop and inner loop)digital data to modulated RF signals which are output at port 130 andreceives incoming RF signals encoded with payload and management (outerloop and inner loop digital data packets) at port 132 and recovers thepackets and routes them according to what type of packet each is andwhat the destination address of the packet is. In other words, the innerloop data path not only includes hardwired data paths 206 and 212 inFIG. 10 it also includes “logical” radio links 208 and 222. In thephysical world, there is only one radio frequency link between each pairof transceivers at side 1 and side 2, and this physical radio frequencylink in each direction carries both payload data packets and managementdata packets. In other words, FIG. 10 is an illustration of the logicaldata paths for both the inner and outer loop between each pair oftransceivers, and there is no actual separate RF link for the inner loopdata path 208 or the inner loop data path 222. Between the two radiobridges, both the outer loop and the inner loop data packets aretransmitted on two single RF data paths, each at a different frequency(or using different code division multiplexing for each direction at thesame frequency) each carrying payload data and management data in onedirection only.

Each radio transceiver has a transmitter and a receiver, one of which isused to transmit or receive (but not both) payload data packets and oneof which is used to transmit or receive but not both management datapackets. To understand this, refer to FIG. 10. FIG. 10 illustrates boththe outer loop data paths 204 and 220 which carry Ethernet payload datapackets and management data packets, and inner loop data paths 208 and222 which carry only management data packets and broadcast data packets.Each of transceivers 201, 203, 205 and 207 contains a transmitter and areceiver. The transmitter of transceiver 201 sends both payload andmanagement packets as RF signals to the receiver of transceiver 205 onouter loop data path 204. Any management packets originating at end #2either from a device coupled to the LAN coupled to port 213 ororiginating from one of the transceivers 203, 207 or 205 and addressedto transceiver 201 are transmitted by the transmitter of transceiver 205in half duplex mode back on inner loop data path 208 to transceiver 201.The transmitter of transceiver 207 sends both payload and managementdata packets to transceiver 203 via outer loop data path 220. Anymanagement or broadcast packet originating from any device coupled tothe LAN coupled to port 209 or originating at any of transceivers 205,201 or 203 and addressed to transceiver 207 are sent via the transmitterof transceiver 203 operating in half duplex mode to transceiver 207 overinner loop data path 222.

Inner loop path segments 206 and 212 carry the Base Control Word andLink Control Word pulses in non RF form. Inner loop path segments 208and 222 carry inner loop management in the form of modulated RF signalsgenerated by radio transceivers 201, 203, 205 and 207. Outer loop pathsegments 200, 215, 218 and 211 carry Ethernet payload data packets innon RF form, and outer loop path segments 204 and 220 carry Ethernetpayload data packets in the form of RF signals modulated with the packetdata generated by radio transceivers 201, 203, 205 and 207.

Block 110 also contains circuit 140 which is a DC-To-DC converter whichis explained more below.

The circuitry on the left half of FIG. 8 is identical to the circuitryin the right half: Circuit 112 corresponds to circuit 110. Injector 170corresponds to injector 106, and power supply 172 corresponds to powersupply 108. Ethernet device 174 can be any Ethernet device.

Returning to the consideration of block 134 in FIG. 8, there iscircuitry inside block 134 shown in detail in FIGS. 9A and 9B whichperforms the segregation of the transmit and receive signals in theCAT5E cable 109 which is necessary to make the embodiments work properlyand avoid the loop condition. The circuit in FIG. 9A is for use in10BaseT and 100BaseT Ethernet networks, and also functions to segregateout the power and ground connections for a DC-to-DC converter 140. Thecircuit in FIG. 9B is for use in 1000BaseT and 10000BaseT Ethernetnetworks, and does not segregate out power and ground wires becausethere are no power and ground wires in 1000BaseT and 10000BaseT CAT5cables. In general, the splitter circuits of FIGS. 9A and 9B are notlimited to two wire or 4 wire transmit and receive pairs. Any number ofwires for the transmit and receive pairs may be used in futurestandards. The teachings of the invention simply contemplate separationof the transmit and receive data paths of the Ethernet port to twoseparate radio transceivers and it does not matter how many wires are ineach path or what kind of cable is used or whether there is or is notpower and ground on the cable.

FIG. 9A shows a splitter with separate power and ground paths coupled tothe power and ground paths of the incoming Ethernet cable. FIG. 9B showsa splitter without these power and ground paths for use in Ethernetnetworks where there is not power and ground on the incoming Ethernetcable. The teachings of the invention do not require any particularconfiguration for the power and ground supplies to the radiotransceivers, i.e., the power can be on the incoming Ethernet cable ornot and the DC-to-DC converters may be on the radio boards or off themand may be omitted altogether if the available DC power is already atthe voltage required by the transceivers. For example, the transceiversmay be on a roof top and a separate solar power and/or utility gridpower supply may be co-located with the transceivers or locatedelsewhere and DC power of the proper voltage or some other voltage whichmay be converted to the proper voltage can be supplied to thetransceivers without coming from the Ethernet link itself.

FIG. 9A is a diagram of the data paths for transmit, receive and powerin the splitter circuit 134 in FIG. 8. It is this circuit whichseparates the transmit and receive pairs of the Ethernet port coupled tothe radio bridges and guides the data on each pair to and from twoseparate half duplex radio bridge transceivers, and it couples innerloop traffic output at an inner loop packet data output port by theradio bridge 114 (the first transceiver) via data path 206 to an innerloop packet data input of radio bridge 116 (the second transceiver).

The DC-to-DC converter 140 receives two wires 141 of +48 VDC and twowires 143 of ground from the CAT5E pipe 109 coming from the injector106. The DC-to-DC converter 140 is a DC-to-DC converter which convertsthe +48 VDC to two separate +5 VDC outputs 122 and 124 which power theradio transceivers 114 and 116. The TX wires 151 of the CAT5 pipe 109couple to a set of transmit nodes of a first Ethernet port 203. Thesetransmit nodes are electrically coupled by conductive traces 151 oncircuit 134 to a set of transmit nodes on Ethernet port 153. Thesetransmit nodes on Ethernet port 153 are coupled by a CAT5 jumper 159 orany jumper suitable for Ethernet data rates to radio transceiver 114.The RX wires 155 of CAT5 pipe 109 couple to a set of receive nodes infirst Ethernet port 203. These receive nodes are coupled by a set ofconductive traces 155 on circuit 134 to a set of receive nodes onEthernet port 157. The receive nodes at Ethernet port 157 coupled byCAT5 jumper 161 to radio transceiver 116. The example shown in FIG. 9Auses two wires for each of the transmit and receive data paths 151 and155 because the assumed Ethernet link is 10BaseT or 100BaseT. Forgigabit Ethernet (1000BaseT standard), the transmit data path 151 is 4wires and the receive data path 155 is 4 wires in 1000BaseT Ethernet,and there are no wires carrying +48 VDC or ground since all 8 wires of aCAT5 1000BaseT cable. An example of the circuit 134 for gigabit Ethernetapplications is shown in FIG. 9B.

Each of the CAT5 jumpers 159 and 161 also use a two wire pair to sendinner loop packets to or receive inner loop packets from one of theradio transceivers. Jumper 159 uses a pair to receive inner loop packetsfrom radio board 114. Jumper 161 uses a pair to transmit inner looppackets to radio board 116.

Tx pair 151 and RX pair 155 of CAT5 pipe 109 coming from the networkdevice to which the radio bridge is connected carry both inner loopmanagement packets and outer loop payload packets. It is up to thesoftware on the radio boards to examine each packet, determine if it isan inner loop packet or an outer loop packet and route it onto the inneror outer loop.

Operations to Route Management Packets onto Inner Loop and PayloadPackets onto Outer Loop

In order for the various embodiments disclosed herein to work properly,it is necessary for the radio bridges to be able to distinguish payloaddata packets from management packets at their various inputs and routethose packets properly. Each radio bridge has two ports for the outerloop payload packet data path and two ports for the inner loopmanagement packet data path. One of each of these pairs of ports is aninput and the other is an output. There is software in the radio bridgesat the various ports which monitor the incoming and outgoing packets todetermine what kind of packets they are, i.e., management or payload.This software routes management packets onto the inner loop and routespayload data packets onto the outer loop.

FIG. 11 is a diagram which illustrates the inner and outer loop datapaths and the various software modules which make the inner loop/outerloop routing decisions. The software modules are indicated by lettersand the various inner loop and outer loop data paths are indicated byreference numbers.

The details of which software modules make which routing decisions andhow the various inner and outer loop data paths are used to getmanagement packets to the various circuits they control and how datapackets get where they need to go follow.

There is a need to allow complete access to each bridge device on thenetwork, by the network system administrator. The administrator needs tosend management data packets to the four radio transceivers to manageand configure and use integrated tools to control them and best optimizethe performance of the network. These options are made available in eachbridge as server functions using the TCP/IP protocol stack. A bridge isone pair of radio transceivers at one side of the connection and theirassociate DC-to-DC converter and splitter circuits. This allows for theuse of TCP and UDP protocols to send management packets as Ethernetpackets over the outer loop payload data path to software in the bridgewhich routes these packets via the inner loop to the appropriate bridgecircuit at side #1 or side #2 to enable management thereof.

In FIG. 11, the data paths which existed in the prior art radio bridgecircuits are shown as dotted lines. The data paths which are shown assolid lines are new paths which have been implemented in the prior artradio bridges to enable the implementation of the inner and outer loopconcept and splitting the traffic of the transmit and receive pairs ofan Ethernet port onto two separate half duplex radio bridges.

The management of the radio bridges requires the use of Telnet, WebBrowser and SNMP and Antenna Alignment Tool server functionalities. Eachof these server functionalities are software modules that exist in eachradio bridge and which listen to specifically assigned port numbers ofthe TCP/IP protocol packets. Therefore, to invoke any one of theseserver functionalities to manage a radio bridge, it is only necessary tosend a TCP/IP packet on the inner loop with its port number field filledwith the specific port number of the tool or server functionality to beinvoked.

This is new over the prior art half duplex radio bridge. In the priorart, the radio bridge was half duplex and involved two radio bridges,one on each side. Each side had one Ethernet port which was connected toone radio bridge. At any particular point in time, both radio bridgeswhere sending in only one direction, hence the half duplex name. Inother words, there was only one data path in each direction that wentthrough both transceivers. Each radio transceiver had a transmitter anda receiver but only the transmitter on one side and the receiver on theother side would be active at any particular moment in time. In thisprior art radio bridge, the Telnet, Web Browser, SNMP and AntennaAlignment Tools existed. Each tool had to monitor all packetstransitioning along each path looking for packets directed to its portnumber, its IP address and its MAC address. There was no loop problembecause the radio bridge was only coupled to one Ethernet port on eachside and, by definition, when a broadcast packet entered one of thoseports, it would not be sent back out the same port.

In order to make this prior art radio bridge into a full duplex radiobridge, it was necessary to add another pair of radio transceivers andthen figure out how to solve the loop problem and how to get themanagement packets to the desired tool or tools in a selected radiotransceiver. The solutions to these problems were to provide an innerloop and add new software to route management packets onto the innerloop and payload data packets onto the outer loop, and to add a splitterwhich allowed the use of only one Ethernet port on each side of thebridge but to segregate the transmit and receive data paths so that eachdata path functioned independently.

In the full duplex radio bridge embodiments disclosed herein, to allowthe use of the Telnet, Web Browser, Antenna Alignment Tool, SNMP, etc.server functions and any new server functions, a need arose to redirectmanagement TCP/IP or UDP packets onto the inner loop. This was done bymaking slight changes to the software of the radio bridge. These changesallow the use of the inner loop and portions of the outer loop to makesure that broadcast and unicast TCP/IP packets are properly delivered toall attached radio transceivers, thereby allowing proper serveroperation anywhere on the network. Whether part of the outer loop isinvolved in routing management packets depends upon the destinationaddress of the management packet and where it originated.

In general, a learning bridge is a basic implementation of atransparent, layer 2 Ethernet learning bridge that learns the networktopology by analyzing the source address of incoming frames from allattached networks.

The preferred embodiments disclosed herein add software modules A, B, C,D, E, F, G, H, J and K to the original circuitry and software of theradio bridge and modifies the original learning bridge code so that thelearning function is disabled under certain circumstance. The originallearning bridge code in the prior art radio transceivers that serve asthe starting point for the embodiments disclosed herein had learningbridge code which watched the traffic passing through the bridge andmodified routing tables kept by the learning bridge code to indicate onwhich side of each radio bridge particular MAC addresses resided. Inother words, when a broadcast packet was sent out both the RF side ofthe bridge and the Ethernet side of the bridge, if the reply came fromthe Ethernet side, the routing tables of the learning bridge code wouldbe modified to indicate that particular MAC address is on the Ethernetside of the bridge. With the addition of the inner loop and the variousrouting and filtering software modules detailed herein to implement thenew embodiments, the learning bridge functionality can get confusedunder eight of the thirty different scenarios for determining the pathback to the original requestor, and therefore, the occurrence of each ofthese eight different scenarios is watched for, and, when one occurs,the learning bridge software is disabled. The specific row numbers ofTable 1 detailing these eight circumstances where the learning bridgefunction need to be disabled are: 9, 11, 12, 13, 15, 17, 18 and 20.

The addition of the specific above identified software modules to theprior art learning bridge is only one example of how the radio bridgescan be modify to implement the inner loop concept central to all theembodiments. Other software configurations can also be used, and it itonly necessary to add some software functionality, regardless ofconfiguration, which performs the following functions:

1) the ability to inspect incoming packets to determine if they areeither broadcast packets or are unicast packets with destinationaddresses which reside in one of the radio bridge transceivers, and, ifso, routing such packets onto the inner loop so that all transceiversreceive them;

2) the ability to inspect packets propagating on the inner loop todetermine if they are response packets, and if they are, routing theseresponse packet onto the outer loop so they can propagate back to theoriginal requestor;

3) the ability to filter packets to prevent looping conditions (packetscannot be sent back to the sender);

4) the ability to minimize sending of packets over the RF radio link byfiltering out packets that might be destined to be transmitted over theRF but which can be removed from the RF queue without adverse affects onoperations;

5) the ability to modify the prior art learning process to keep it fromgetting confused under certain circumstances (which can be determinedfrom inspection of Table 1 below for the row numbers specified above—alleight of these circumstances involve situations where the input port andoutput are different transmissions mediums) and making improper changesto the routing tables under these circumstances.

Any radio bridge transceiver which has either hardware or software orsome combination thereof which can perform the above five identifiedfunctions will suffice to practice the genus of the invention.

The changes needed to the prior art learning bridges needed to make themin accordance with the embodiment disclosed herein also allow allresponse packets from all attached radio transceivers to be directedback to the requestor for proper operation. These changes also allow theradio transceiver to interoperate talk to each other using the TCP/IPprotocol stack, i.e., each radio transceiver tool can generate an TCP/IPpacket addressed to any other port, IP address and MAC address on thenetwork.

The primary software use of the inner loop is to make sure that anylocal external Ethernet packet that is destined for a radio transceiverconnected to the receiving data path can receive the packets and respondback to the requestor. In the preferred embodiment, the system isdesigned to operate using equipment from a single vendor by requiringthe first three bytes of the MAC address of any TCP/IP management packetto be a specific predetermined identifier indicating that the packet wasintended to manage one of the four radio transceivers of the two radiobridges one at each end. This prevents TCP/IP management packets nothaving this predetermined identifier and which are not intended tomanage one of the four radio transceivers from being routed onto theinner loop. The use of bridge MAC addresses, by a specific manufacturer,only prevents interoperability between vendors for managing the bridges,and is not required in all embodiments. In some embodiments, thesoftware that makes the discrimination and routing decisions does nothave this requirement. The only software restriction on the use of theinner loop for network management activities is that all attached bridgedevices have the same IEEE three-octet OUI company ID used to generateunique MAC address for each Ethernet device from a specificmanufacturer.

In FIG. 11, the bridge on side 1 includes radio transceivers 201 and203, and the bridge on side 2 consists of radio transceivers 205 and207. Each of radio transceivers 201 and 207 are identical functionally,and radio transceivers 203 and 205 are identical functionally. Ethernetport 209 on side 1 has its transmit pair 200 coupled to transceiver 201and has its receive pair 211 coupled to transceiver 203. At side 2,transceiver 213 has its receive pair 215 coupled to transceiver 205 andhas its transmit pair 218 coupled to transceiver 207.

The outer loop in FIG. 11 is comprised at least of data paths 200, 204,210 and 215 going in one direction and 218, 220, 224 and 211 coming backin the other direction. The inner loop data path is comprised at leastof data paths 202, 206, 226, 222, 208, 214, 212 and 216. Other datapaths, software modules and the TCP/IP and learning bridge code insidethe radio bridge transceivers are also involved in transportingmanagement packets, as will be detailed in Table 1 below. Onlymanagement TCP/IP and reply TCP/IP packets flow on these inner loop datapaths, and it is the responsibility of the routing software modules Aand G to determine which packets are management or reply packets androute them onto the appropriate data path.

The functionality of the prior art radio bridges modified to be withinthe genus of new embodiments disclosed herein is detailed in theflowchart of FIG. 16. More specifically, FIG. 16, comprised of FIGS.16A, 16B, 16C and 16D, is a flowchart of the functionality of thetransceivers of the prior art radio bridges as modified by the additionof various routing and filtering functionality (which can be implementedeither in hardware or software) to be within the genus of newembodiments disclosed herein. FIG. 16A is a flow diagram of thefunctionality implemented by the various software modules of thetransceiver 201 in FIG. 11. Incoming packets arrive from the Ethernetnetwork port 209 arrive on data path 200 where function 217A, (part ofthe software module A) determines if each incoming packet is a broadcastor a unicast packet having a predetermined number called an OUI number(manufacturer specific) as part of its destination MAC address. In theclaims, routing software module A will be called a routing circuitbecause it is generally implemented using a suitably programmedmicroprocessor. The routing of packets onto data path 202 is done solelyby the routing circuit 217, but the routing of packets onto the outerloop data path 204 is done by central circuit 282 in transceiver 201(similarly for routing circuit 235 in transceiver 207).

All of these incoming packets on data path 200 are also coupled via datapath 238 to circuit 282 also regardless of the processing of function217. Each transceiver has a circuit 282 which is generally amicroprocessor programmed to carry out management functions andimplement a learning bridge which learns the network topology fromanalyzing the source and destination addresses of packets passingthrough the bridge. The circuit 282 will be referred to herein as thecentral circuit or learning bridge code from time to time. However, itis really a programmed microprocessor in most embodiments which is priorart except for one modification. In the embodiments disclosed herein,the bridge code is modified to recognize one of the eight situationsidentified elsewhere herein wherein the bridge code could becomeconfused and make incorrect entries in the routing table. Thesesituation arise from the fact that in the embodiments disclosed hereinthere is an inner loop, while in the prior art half duplex radio bridgetransceivers there was no inner loop.

It is because there is an inner loop in the embodiments disclosed hereinwhich makes it necessary to have a routing function to recognizeselected management packets and put them on the inner loop while alsorecognizing payload packets and putting them on the outer loop as wellas recognizing management packets which need to be sent on the outerloop to get to the transceiver to which they are addressed. This routingfunction is carried out in transceiver 201 by software module A at 217and the circuit 282. Specifically, software module A at 217 (and itscounterpart software module A at 235 in transceiver 207) operates asfollows to recognize certain management packets and route them onto theinner loop. If a packet arriving on path 200 is either a broadcast ortransceiver specific unicast packet, it is a management packet whichneeds to be routed onto the inner loop (in transceiver 207, routersoftware A recognizes broadcast packets and transceiver specific unicastpackets and puts them onto the inner loop). A “transceiver specific”unicast packet is one which has as the first three bytes (the “OUIcode”) of the destination MAC address a predetermined number which ismanufacturer specific. In the claims, the OUI code is referred to as a“predetermined number”. If those three bytes are the predeterminednumber it means that the packet needs to be analyzed by the centralcircuit (286, 276 or 280) of one of the other transceivers. In such acase, the packet is routed to function 217B where it is tagged as amanagement packet coming from the attached Ethernet network and isforwarded onto the inner loop data paths 202 and 206 where it isreceived by filter module F at 284 in FIG. 16B. All broadcast andunicast packets routed onto data path 202 (or data path 216 intransceiver 207) are tagged.

FIG. 16B shows the functionality of transceiver 203. Filter module F at284 (referrred to in the claims sometimes as a first filtering circuitbecause it is usually implemented as a programmed microprocessor) intransceiver 203 determines if the incoming packet on data path 206originated in transceiver 203 so that such packets can be deleted so asto prevent a looping condition that would suck up all the inner loopbandwidth. If the arriving packet did originate in bridge 203, thepacket is tagged for deletion by function 284 by setting a delete flag,but if the arriving packet did not originate in transceiver 203, it isforwarded to software module G shown at 219A, 219B and 219C (referred toin the claims as a second filtering circuit because it is usuallyimplemented using a programmed microprocessor) and the delete flag isnot set. Function 219A receives the packet and deletes it in function219B if the delete flag is set. Function 219C receives packets output byfunction 284 and determines if they were tagged by function 217A in FIG.16A as having come from the external network. Function 219C is a gatewayto the outer loop and its function is to only allow non-taggedmanagement packets to get to the outer loop since non tagged managementpackets are response packets generated by a transceiver in the radiobridge which need to be routed back to the original requestor. Thus,function 219C only outputs non-tagged packets onto path 226. Since onlytagged management packets and untagged response packets arrive on datapath 206, only non tagged response packets get past filter function 219C(filter G) onto path 226. Filter function J at 221 drops any taggedpackets to prevent looping conditions by keeping tagged packets off datapath 211 which leads back to Ethernet port 209 in FIG. 11. Taggedpackets may have come from port 209 so they are not to be sent back toit to prevent looping. Filter function J is also only required inembodiments where the transceiver radio boards are purchased from an OEMwho wrote their operating systems in such a way that it is possible fortagged packets to sometimes be routed by a multiplexer function in theoperating system code toward path 211. If the radio transceivers were tobe built “from scratch” by the inventor so that tagged packets wouldnever get routed toward path 211 from the central circuit of transceiver203, filter function J at 221 would be unnecessary and that would be analternative embodiment.

Function 219A forwards both tagged and non-tagged packets which have notbeen marked for deletion along data path 230 to learning bridge softwareprocess 286A. The learning bridge function 286A determines if the packetis addressed to transceiver 203, and, if so, forwards it to learningbridge function 286B. Function 286B examines the packet addresses,updates the routing tables to reflect whatever is learned about networktopography (except in one of the eight cases identified herein—see thecomments below on how the learning bridge function is modified) and ifthe packet is a management packet addressed to transceiver 203, whatevermanagement function is listening to the port address in the packetheader will be invoked to do whatever the management packet isrequesting. The learning bridge functions 286B in FIGS. 16B and 282D inFIG. 16A and their counterparts in FIGS. 16C and 16D must be modifiedfrom their prior art states to include a function which looks for one ofthe eight cases where the learning bridge can get confused and disablethe process of updating the routing tables. This code looks to determineupon which port of the transceiver an incoming management packet arrivedand caches the source MAC address and associates the stored MAC addresswith the port upon which it arrived in an alternate routing table. Thenthat information is used each time an outgoing management packet is tobe sent by intercepting the lookup to the standard routing table anddiverting the lookup to the alternate routing table. The destination MACaddress of the packet being built for transmission is looked up in thealternate routing table and the port associated with that destinationMAC address is used to determine the routing of the outgoing packet.

Learning bridge function 286A forwards any broadcast packets (which arealways deemed to be management packets) and any tagged managementpackets or response packets addressed to any transceiver other than 203to filter software modules K and H at 232A and 234A. Function 232A onlypasses management packets which are being sent on the inner loop fromthis transceiver 203 out RF output inner loop link 222. This does notmean that they were originated by transceiver 203. These packets mayalso be tagged management packets addressed to bridge 207 or responsepackets addressed to a device on bridge 207 which sent a managementpacket to some other transceiver in the radio bridge. Any packet whichdoes not meet the filter criteria is dropped in function 232B.

The packets forwarded by function 232A are received by filter function Hat 234A which functions to filter out packets having source MACaddresses in the encapsulated Ethernet packet which match thedestination MAC address in the RF packet header. If they match, thisindicates the packets to be sent to transceiver 207 were sourced bytransceiver 207 and a possible looping condition is present. If there isa match, the packet is dropped at 25B. This also prevents unnecessaryconsumption of bandwidth on RF link 222.

Packets arriving at transceiver 203 via RF outer loop data path 220 anddata path 225 are received by central circuit 286B (management functionsand learning bridge function) where the learning process happens toupdate the routing tables except in one of the eight cases identifiedabove. If the packet is a management packet addressed to transceiver203, the management function listening to the port number identified inthe packet is addressed and launches to do whatever management functionthe packet is requesting.

If the packet arriving from 286A is a payload packet, learning bridgefunction 286B forwards it to filter software module J at 221 where thepacket is dropped if it is a tagged packet but forwarded onto data path211 if it is not a tagged packet (only management packets arriving fromthe external network and addressed to one of the transceivers of theradio bridge are tagged). This is how payload data packets get acrossthe radio bridge from Ethernet port 213 in FIG. 11 to Ethernet port 211.

Returning to the consideration of FIG. 16A, central circuit 282Areceives packets on data paths 238 and determines whether this packet isa management packet addressed to transceiver 201. If it is, the packetis forwarded to learning bridge function 282B where the learning bridgelearns whatever can be learned about the network topology from thepacket header information, except in one of the eight cases identifiedherein where the learning bridge function is disabled. That learnedinformation is stored in routing tables kept by the learning bridgecode. If the packet is a management packet addressed to transceiver 201,whatever management functionality 282D that is listening to the portnumber contained in the packet header is invoked to do the requestedmanagement function, and a response management packet is generated. Therouting tables in the learning bridge are consulted to determine whetherthe device to which the response packet is to be sent is on the RF sideof the bridge or the Ethernet side. If the device to which the responsepacket is addressed is determined from the routing table to be on theEthernet side of transceiver 201, the response packet is launched ondata path 236 for coupling to data path 206 and inner loop transmissionto filter function F shown at 284 in FIG. 16B. Data path 236 will carryboth non tagged response packets to management packets or non taggedmanagement packets generated in transceiver 201 and addressed to eithertransceiver 203 or 207. If the response packet is directed to a unitcoupled to the RF side of the radio bridge, the response managementpacket is output on data path 241 to filter functions B and C shown at243A and 243B and 245A and 245B in FIG. 16A. Filter functions 243A and245A appear to do the same thing, and their existence in this embodimentis a function of the fact that the operating system of the radiotransceiver boards was not written by the inventor but was written bythe manufacturer of the prior art radio board which was modified inaccordance with the teachings of the invention. The existence of filterfunction 245A is necessary because the filter function 243A occursearlier in the code line of the radio transceiver, and, in somecircumstances, tagged packets can attempt to be routed to the outer loopat later points in the transceiver code. Filter function 245A and 245Bdetects these tagged packets and drops them before they get to the outerloop.

Filter function B at 243A determines if the packet arriving on 241 istagged as a management packet coming from an outside network and, ifyes, drops it as represented by block 243B. Tagged packets aremanagement packets that came from a connected packet network and whichwere routed onto the inner loop because they had a predetermined numbercalled an OUI code in their destination MAC address. Response managementpackets are never tagged. Thus, the response packet generated bylearning bridge code 282D is passed through filter function B to outerloop data path 204 for transmission to transceiver 205. However, anytagged management packet which happened to find its way onto data path241 from function 282A would be dropped by filter function B at 243A. Ifthe packet received by function 243A is not to be dropped, function 243Aencapsulates into an outer RF packet which encapsulates the Ethernetpacket. Filter function B is not necessary in all embodiments. Filterfunction B is only necessary in embodiments where a radio transceiver ispurchased from a vendor which wrote the operating system and thatoperating system includes a multiplexer function which sometimes decidesto send tagged packets on data path 241. If the radio boards were to bemanufactured “from scratch” and all their code were to be written by theinventor, that code would never send a tagged packet on data path 241,and filter function B would not be necessary.

Filter function C at 245A also receives all the data packets travellingon data path 241 from either learning bridge 282D or function 282A anddoes the same things as functions 243A and 243B. The difference is thatfunctions 243A and 243B, in this embodiment, are a failsafe to preventtransmission over the RF link of packets forwarded by the OEM operatingsystem code of the radio which is not under control of the inventors.Any packets passing through the gauntlet of filter and routing functionsdescribed herein and arriving at data path 204 are converted byconventional circuitry from data packets into RF signals andtransmitted. Payload packets addressed to the other network will arriveon path 200 and pass through function 282A unchecked and will passthrough filter functions B and C unhindered to data path 204 becausepayload data packets are never tagged.

Transceiver 201 can also receive management data packets on innerloop-RF data path 208 from transceiver 205. These packets are recoveredfrom the radio frequency signals by the prior art physical layercircuitry of the transceiver and output to filter function E shown at257A. This filter function E determines if the incoming packet has asource MAC address of the Ethernet packet which was encapsulated in theRF packet to determine if the packet was sourced by transceiver 201. Ifit was sourced by transceiver 201, the packet is dropped, as representedby block 257B. If the packet is not dropped, it is forwarded to filterfunction D at 255A. This function 255A determines if the incoming packetis a tagged management packet coming in from an outside network which isnot addressed to transceiver 201, and, if that is the case, drops thepacket in 255B. Tagged management packets addressed to transceiver 201will be output on path 251 to central circuit 282C which determineswhether the incoming management packet is addressed to this transceiver.If it is, the packet is sent to central circuit 282D where the topologylearning function happens (under predetermined circumstances), andwhatever management function the packet is intended to invoke (if thatis the case) is invoked. If the incoming packet is a response packet tosome packet generated earlier by some function in the central circuit,it is directed to whatever management function code generated theoriginal management packet. If the incoming management packet is fromsome device which is not in the routing table and is addressed totransceiver 201, the central circuit will carry out the managementfunction, generate a response packet and then determine from the routingtable that it is not known whether the device to which the responsepacket is to be sent is on the RF side or the network side of thetransceiver. In such a case, the central circuit will forward theresponse packet both toward the inner loop packet network port 206 andthe RF outer loop output port 204. This functionality is implemented inall the central circuits of all the transceivers in both bridges whenthere is no entry in their routing tables for the device to which apacket is to be sent. In such cases, the central circuit route thepacket out with the data path headed toward the RF side of thetransceiver and the data path headed toward the network side of thetransceiver.

The packets arriving at 282C are never payload data packets but theycould be either response management packets addressed to bridge 203 or207 or management packets sourced in transceiver 205 and addressed toeither transceiver 203 or 207. Such packets will be forwarded by 282Conto data path 236 for output on inner loop data path 206.

FIGS. 16C and 16D show the same functionality as was just described fortransceivers 203 and 205, but for transceivers 205 and 207. The variousfunctional blocks and data paths have been labeled with the referencenumbers of transceivers 205 and 207 in FIG. 11, but no furtherexplanation will be given as the functions of these routing and filterblocks are the same as their counterparts in transceivers 201 and 203.

The following packet flow description assumes that communication isfunctioning correctly over paths 204, 208, 222 and 220. What that meansis the transceiver 205 is properly configured to talk to transceiver201, and transceiver 203 is properly configured to talk to transceiver207. Properly configured means that the frequency, bandwidth, encryptiontype and opposite unit's MAC address have all been set properly in theconfiguration data of the transceiver.

Side 1

All packets from an attached local wired network Ethernet port 209 aretransmitted to transceiver 201 on path 200 and all packets to betransmitted to the Ethernet port 209 are transmitted from transceiver203 on paths 224 and 211. If the packet on 200 is a broadcast packet forany device or is a unicast packet, the routing software A at 217 routesthe packet onto both the outer loop data path 204 (via data path 238,learning bridge code 282 and data path 241) as well as onto the localloop data path 202 so that the broadcast and unicast packets reach radiotransceivers 201, 203, 205 or 207 in addition to being sent across thelink on the outer data path to Ethernet port 213 (the same thing happensin the bridge on side 1). In addition, if the packet arriving on path200 is a broadcast or unicast packet addressed to one of thetransceivers and is a management packet, then routing software A at 217tags the management packet as coming in from the external Ethernetnetwork. In such a case, the broadcast or unicast packet is sent to theother transceivers via data path 202. Tagged packets are only allowed topropagate on the inner loop, and the filter software will kill such apacket if it is on a path which would take it to the outer loop. Thetags assist the routing software modules to properly route inner looppackets and prevent possible inner loop infinite looping conditions.

If the packet arriving at routing software module A at 282 is not amanagement packet addressed to transceiver 201, it is sent out path 204(via paths 238 and 241 and the bridge code of transceiver 201) totransceiver 205 for processing. The packets sent out outer loop datapath 204 can be payload data packets destined for a device connected tothe remote Ethernet network (port 213) or they can be broadcast orunicast management packets addressed to transceiver 205 whichtransceiver 205 needs to see.

If the packet arriving on data path 200 is a management packet addressedto transceiver 201, software module A routes it onto paths 238 and 202.The bridge code 282 of transceiver 201 then processes the managementpacket, and generates one or more response packets. This response packetis sent out via data paths 236 and 206 to the inner loop. The responsepacket is analyzed by routing software G at 219 and sent out data path226 to the outer loop data path 211 as a packet sourced by transceiver201. Data path 226 terminates at a filter software module J shown at 221which merges the response packet with data packets from data path 224onto data path 211 where it travels back to the requestor.

Inner loop management packets propagating on path 202 are directed ontothe inner loop path 206 for processing by the transceivers 203 and 207.These packets on data path 206 are inner loop packets which are alwaysbroadcast packets, unicast management packets or response packets. Allthese packets are TCP/IP packets, and the protocol to establishconnections between devices on the inner loop is therefore the same asis used in TCP/IP protocol connects in the prior art such as on theinternet.

If the packets are tagged in routing software A at 217 as having comefrom the external attached Ethernet network, they are routed onto datapath 206 via data path 202 to be analyzed by routing software G at 219in transceiver 203. If the packets arriving on 206 are broadcastpackets, any unicast packet that are not addressed to transceiver 203,they are routed by software module G at 219 onto inner loop data path222 (via data paths 230, bridge code 286 and data path 249 and filtermodules K and H at 232 and 234), and they are also routed onto data path226. If the packet arriving on path 206 is a tagged management packetwhich is addressed to transceiver 203, then routing software G at 219transmits the packet to bridge code 286 via 230. Bridge code 286 doesthe requested management function and generates one or more responsepackets which are sent out paths 224 and 211 to be returned to therequestor and are also sent out data paths 249 through filter code H andK at 232 and 234 and data path 222 to transceiver 203 where they arerouted back to the requestor coupled to Ethernet port 213 via filtercode D and E at 229 and 288, data path 253, bridge code 276, data path212, filter code F at 240, routing code G at 237, data path 214, filtercode J at 239 and data path 215.

Packets coming into transceiver 205 on outer loop data path 204 could beeither payload data packets or management packets. They are analyzed bybridge code 280 in transceiver 205, and if the packet is not addressedto bridge 205, it is sent out data path 210 and data path 215 to theattached Ethernet network coupled to port 213. This is how payload datapackets traverse transceivers 201 and 205 via the outer loop to get fromEthernet port 209 to Ethernet port 213.

Any response packet from any device connected to port 213 will come backvia port 213 and be placed on data path 218. If the packet on outer looppath 204 is a management packet addressed to transceiver 205, therequested management function is performed, and a response of one ormore packets is generated by bridge code 280 in transceiver 205 and sentout on data path 227 and inner loop data path 208 to transceiver 201.There, the packet is filtered by new software modules D and E at 255 and257. Filter module D only allows packets addressed to transceiver 201 topass and response packets from transceiver 205 to continue on path 251.Filter software E at 257 drops any packet which was originally sent bytransceiver 201 to prevent looping. Since, in this example the packetarriving on line 208 is a response packet from transceiver 205, it isforwarded onto data path 206 (via code D, E, path 251, bridge code 282and data path 236 to path 206. The response packet in this example isanalyzed by software module G at 219, and sent out path 226 for mergingwith packets from data path 224 and sent back to the requestor via datapath 211.

Packets coming in to transceiver 207 on inner loop data path 222 areanalyzed to determine if they are addressed to transceiver 207. If theyare not addressed to transceiver 207, the packet is dropped by filtersoftware D at 229. If the packet is addressed to transceiver 207, themanagement packet is processed by bridge code 276, and one or moreresponse packets are generated and sent out paths 223 and 220. Thesepackets are filtered by filter software modules B and C at 231 and 233.Filter software module B at 231 drops any management packets that havebeen tagged as having come from the external network. Filter softwaremodule C at 233 does the same thing (for packets coming throughdifferent paths through the code). Since, in this example, the packetsare response packets generated by transceiver 207, they are forwarded byfilter software B and C to transceiver 203 via data path 225, bridgecode 286, and data paths 224 and 211 for transmission back to therequestor.

Side 2

All packets from an attached local wired network Ethernet port 213 aretransmitted to transceiver 207 on path 218 and all packets to betransmitted to the Ethernet port 213 are transmitted from transceiver205 on paths 210 and 215. If the packet on 218 is a broadcast packet forany device or is a unicast packet, the routing software A at 235 routesthe packet onto both the outer loop data path 220 (via data paths 274and 223 as well as onto the local loop data path 216 so that thebroadcast and unicast packets reach radio transceivers 201, 203, 205 or207 in addition to being sent across the link on the outer data path toEthernet port 209 (the same thing happens in the bridge on side 1). Inaddition, if the packet arriving on path 218 is a broadcast or unicastpacket addressed to one of the transceivers and is a management packet,then routing software A at 235 tags the management packet as coming infrom the external Ethernet network. In such a case, the broadcast orunicast packet is sent to the other transceivers via data path 216.Tagged packets are only allowed to propagate on the inner loop, and thefilter software will kill such a packet if it is on a path which wouldtake it to the outer loop. The tags assist the routing software modulesto properly route inner loop packets and prevent possible inner loopinfinite looping conditions.

If the packet arriving at routing software module A at 235 is not amanagement packet addressed to transceiver 207, it is sent out path 220(via paths 274 and 223 and the bridge code of transceiver 207) totransceiver 203 for processing. The packets sent out outer loop datapath 220 can be payload data packets destined for a device connected tothe remote Ethernet network (port 209) or they can be broadcast orunicast management packets addressed to transceiver 203 whichtransceiver 203 needs to see.

If the packet arriving on data path 218 is a management packet addressedto transceiver 207, software module A routes it onto paths 274 and 216.The bridge code 276 of transceiver 207 then processes the managementpacket, and generates one or more response packets. This response packetis sent out via data paths 278 and 212 to the inner loop. The responsepacket is analyzed by routing software G at 237 and sent out data path214 to the outer loop data path 215 as a packet sourced by transceiver207. Data path 214 terminates at a filter software module J shown at 239which merges the response packet with data packets from data path 210onto data path 215 where it travels back to the requestor.

Inner loop management packets propagating on path 216 are directed ontothe inner loop path 212 for processing by the transceivers 205 and 201.These packets on data path 212 are inner loop packets which are alwaysbroadcast packets, unicast management packets or response packets. Allthese packets are TCP/IP packets, and the protocol to establishconnections between devices on the inner loop is therefore the same asis used in TCP/IP protocol connects in the prior art such as on theInternet.

If the packets are tagged in routing software A at 235 as having comefrom the external attached Ethernet network, they are routed onto datapath 212 via data path 216 to be analyzed by routing software G at 237in transceiver 205. If the packets arriving on 212 are broadcastpackets, any unicast packet that are not addressed to transceiver 205,they are routed by software module G at 237 onto inner loop data path208 (via data paths 228, bridge code 280 and data path 227 and filtermodules K and H at 272 and 270), and they are also routed onto data path214. If the packet arriving on path 212 is a tagged management packetwhich is addressed to transceiver 205, then routing software G at 237transmits the packet to bridge code 280 via 228. Bridge code 280 doesthe requested management function and generates one or more responsepackets which are sent out paths 210 and 215 to be returned to therequestor and are also sent out data paths 227 through filter code H andK at 272 and 270 and data path 208 to transceiver 205 where they arerouted back to the requestor coupled to Ethernet port 209 via filtercode D and E at 255 and 257, data path 251, bridge code 282, data path206, filter code F at 284, routing code G at 219, data path 226, filtercode J at 221 and data path 211.

Packets coming into transceiver 203 on outer loop data path 220 could beeither payload data packets or management packets. They are analyzed bybridge code 286 in transceiver 203, and if the packet is not addressedto bridge 203, it is sent out data path 224 and data path 211 to theattached Ethernet network coupled to port 209. This is how payload datapackets traverse transceivers 207 and 203 via the outer loop to get fromEthernet port 213 to Ethernet port 209.

Any response packet from any device connected to port 209 will come backvia port 209 and be placed on data path 200. If the packet on outer looppath 220 is a management packet addressed to transceiver 203, therequested management function is performed, and a response of one ormore packets is generated by bridge code 286 in transceiver 203 and sentout on data path 249 and inner loop data path 222 to transceiver 207.There, the packet is filtered by new software modules D and E at 229 and288. Filter module D only allows packets addressed to transceiver 207 topass and response packets from transceiver 203 to continue on path 253.Filter software E at 288 drops any packet which was originally sent bytransceiver 207 to prevent looping. Since, in this example the packetarriving on line 222 is a response packet from transceiver 203, it isforwarded onto data path 212 (via code D, E, path 253, bridge code 276and data path 278 to path 212. The response packet in this example isanalyzed by software module G at 237, and sent out path 214 for mergingwith packets from data path 210 and sent back to the requestor via datapath 215.

Packets coming in to transceiver 201 on inner loop data path 208 areanalyzed to determine if they are addressed to transceiver 201. If theyare not addressed to transceiver 201, the packet is dropped by filtersoftware D at 255. If the packet is addressed to transceiver 201, themanagement packet is processed by bridge code 282, and one or moreresponse packets are generated and sent out paths 241 and 204. Thesepackets are filtered by filter software modules B and C at 243 and 245.Filter software module B at 243 drops any management packets that havebeen tagged as having come from the external network. Filter softwaremodule C at 245 does the same thing (for packets coming throughdifferent paths through the code). Since, in this example, the packetsare response packets generated by transceiver 201, they are forwarded byfilter software B and C to transceiver 205 via data path 247, bridgecode 280, and data paths 210 and 215 for transmission back to therequestor.

Table 1 below documents all the possible payload data packet paths andall the possible management data packet paths and details the data pathnumbers that each type packet propagates upon for each scenario. Eachrow in the table is one scenario.

TABLE 1 Packet Packet Request Response Extra Path And Source DestinationPaths Paths Remarks Ethernet Port 209 Transceiver 201 200, 217, 238 236,206, 284, 217, 202, 206, 284, 219, 219, 226, 221, 230, 286, 249, 232,234, 211 222, 288 where it is stopped by filter action. The requestpath, response path and extra paths are graphically illustrated in FIG.12. Ethernet Port 209 Transceiver 203 200, 217, 202, 224, 221, 211 217,238, 282, 241, 243, 206, 284, 219, 245, 204, 247, 280, 210, 230, 286239, 215 and out 213. FIG. 13 illustrates the request path and theresponse path and extra paths. Ethernet Port 209 Transceiver 205 200,217, 238, 227, 272, 270, 217, 202, 206, 284, 219, 282, 241, 243, 208,257, 255, 230, 286, 249, 232, 234, 245, 204, 247 251, 282, 236, 222, 288206, 284, 219, 226, 221, 211 Ethernet Port 209 Transceiver 207 200, 217,202, 223, 231, 233, 217, 238, 282, 241, 243, 206, 284, 219, 220, 225,286, 245, 204, 247, 280, 210, 230, 286, 249, 224, 221, 211 239, 215 232,234, 222, 288, 229, 253 Ethernet Port 213 Transceiver 207 218, 235, 274278, 212, 240, 235, 216, 212, 240, 237, 237, 214, 239, 228, 280, 227,272, 270, 215 208, 257 Ethernet Port 213 Transceiver 205 218, 235, 216,210, 239, 215 235, 274, 276, 223, 231, 212, 240, 237, 233, 220, 225,286, 224, 228 211 Ethernet Port 213 Transceiver 203 218, 235, 274, 249,232, 234, 235, 216, 212, 240, 237, 276, 223, 231, 222, 288, 229, 228,280, 227, 272, 270, 233, 220, 225 253, 276, 278, 208, 257 212, 240, 237,214, 239, 215 Ethernet Port 213 Transceiver 201 218, 235, 216, 241, 243,245, 235, 274, 276, 223, 231, 212, 240, 237, 204, 247, 280, 233, 220,225, 286, 224, 228, 280, 227, 210, 239, 215 211 272, 270, 208, 257, 255,251 Transceiver 201 Transceiver 203 236, 206, 284, 249, 232, 234, 219,226, 221, 211 & 219, 230 222, 288, 229, 237, 214, 239, 215 253, 276,278, 212, 240, 237, 228, 280, 227, 272, 270, 208, 257, 255, 251Transceiver 201 Transceiver 205 241, 243, 245, 227, 272, 270, none 204,247 208, 257, 255, 251 Transceiver 201 Transceiver 207 236, 206, 284,278, 212, 240, 219, 226, 221, 211 & 219, 230, 286, 237, 228, 280, 237,214, 239, 215 249, 232, 234, 227, 272, 270, 222, 288, 229, 208, 257,255, 253 251 Transceiver 203 Transceiver 201 249, 232, 234, 236, 206,284, 219, 226, 221, 211 & 222, 288, 229, 219, 230 237, 214, 239, 215253, 276, 278, 212, 240, 237, 228, 280, 227, 272, 270, 208, 257, 255,251 Transceiver 203 Transceiver 205 249, 232, 234, 227, 272, 270, 219,226, 221, 211 & 222, 288, 229, 208, 257, 255, 237, 214, 239, 215 253,276, 278, 251, 282, 236, 212, 240, 237, 206, 284, 219, 228 230Transceiver 203 Transceiver 207 249, 232, 234, 223, 231, 233, none 222,288, 229, 220, 225 253 Transceiver 207 Transceiver 201 278, 212, 240,236, 206, 284, 219, 226, 221, 211 & 237, 228, 280, 219, 230, 286, 237,214, 239, 215 227, 272, 270, 232, 234, 222, 208, 257, 255, 288, 229, 253251 Transceiver 207 Transceiver 203 223, 231, 233, 249, 232, 234, none220, 225 222, 288, 229, 253 Transceiver 207 Transceiver 205 278, 212,240, 227, 272, 270, 219, 226, 221, 211 & 237, 228 208, 257, 255, 237,214, 239, 215 251, 282, 236, 206, 284, 219, 230, 286, 249, 232, 234,222, 288, 229, 253 Transceiver 205 Transceiver 207 227, 272, 270, 278,212, 240, 219, 226, 221, 211 & 208, 257, 255, 237, 228 237, 214, 239,215 251, 282, 236, 206, 284, 219, 230, 286, 249, 232, 234, 222, 288,229, 253 Transceiver 205 Transceiver 201 227, 272, 270, 241, 243, 245,none 208, 257, 255, 204, 247 251 Transceiver 205 Transceiver 203 227,272, 270, 249, 232, 234, 219, 226, 221, 211 & 208, 257, 255, 222, 288,229, 237, 214, 239, 215 251, 282, 236, 253, 276, 278, 206, 284, 219,212, 240, 237, 230 228 Ethernet Port 209 Ethernet Port 213 200, 217,238, 218, 235, 274, none 282, 241, 243, 276, 223, 231, 245, 204, 247,233, 220, 225, 280, 210, 239, 286, 224, 221, 215 211 Ethernet Port 213Ethernet Port 209 218, 235, 274, 200, 217, 238, none 276, 223, 231, 282,241, 243, 233, 220, 225, 245, 204, 247, 286, 224, 221, 280, 210, 239,211 215 Transceiver 201 Ethernet Port 209 236, 206, 284, 200, 217, 238219, 230, 286, 249, 232, 219, 226, 221, 234, 222, 288 211 Transceiver203 Ethernet Port 209 224, 221, 211 200, 217, 202, 217, 238, 282, 241,253, 206, 284, 219, 245, 204, 247, 280, 210, 230 239, 215 Transceiver205 Ethernet Port 209 227, 272, 270, 200, 217, 238, 219, 230, 286, 249,232, 208, 257, 255, 282, 241, 243, 234, 222, 288 251, 282, 236, 245,204, 247 206, 284, 219, 226, 221, 211 Transceiver 207 Ethernet Port 209223, 231, 233, 200, 217, 202, 217, 238, 282, 241, 243, 220, 225, 286,206, 284, 219, 245, 204, 247, 280, 210, 224, 221, 211 230, 286, 249,239, 215 232, 234, 222, 288, 229, 253 Transceiver 201 Ethernet Port 213241, 243, 245, 218, 235, 216, 235, 274, 276, 223, 231, 204, 247, 280,212, 240, 237, 233, 220, 225, 286, 224, 210, 239, 215 228, 280, 227, 211272, 270, 208, 257, 255, 251 Transceiver 203 Ethernet Port 213 249, 232,234, 218, 235, 274, 237, 228, 227, 272, 270, 222, 288, 229, 276, 223,231, 208, 257 253, 276, 278, 233, 220, 225 212, 240, 237, 214, 239, 215Transceiver 205 Ethernet Port 213 210, 239, 215 218, 235, 216, 235, 274,276, 223, 231, 212, 240, 237, 233, 220, 225, 286, 224, 228 211Transceiver 207 Ethernet Port 213 278, 212, 240, 218, 235, 274 237, 228,280, 227, 272, 237, 214, 239, 270, 208, 257 215FIG. 17 is a block diagram showing another configuration for the radiobridge where the splitting of the transmit and receive data paths of theEthernet port are done at a splitter 300 located inside a building atthe location of the Ethernet port 302 and the radio boards 304 and 306are physically separated such as up on the roof of the building. Theradio boards have onboard DC-to-DC converters 308 and 310. In analternative embodiment, the DC-to-DC converter can be external to theboards and co-located with the radio boards.

Features of various embodiments disclosed herein are as follows:

1) The size of the full duplex radio bridge is much less than a ACpowered router coupled to a hardwired local area network.2) The full duplex radio bridge appears to the other network elements tobe one network device so looping cannot occur.3. Having all the payload data going from side one to side twotransmitted simultaneously with all the payload data going from side twoto side 1 because of full duplex operation, causes a 50% improvement inthroughput because the radio bridge does not have to switch fromtransmit to receive.4. The radio bridge structure allows management packets to betransmitted to individual transceivers so that each radio bridge pathgoing in each direction can be separately configured. This allowsasymmetric network design for high speed downloads and lower speeduploads and saves spectrum because the upstream and downstream do notneed to consume the same amount of bandwidth.5. Management access is provided to each of the four transceivers in theradio bridge so each can be separately configured and managed.6. The implementation allows the system to be completely functional inmultipoint system architectures. This means that any single bridge canbe configured to communicate with multiple other devices using the sametwo RF data paths (one upstream and one downstream). FIG. 14 is adiagram of a multipoint architecture. Ethernet network 300 is coupled tofull duplex bridge 302 via a single Ethernet port 213. The full duplexbridge 302 is the equipment illustrated on side 2 of FIG. 13. The fullduplex bridge 302 can be simultaneously coupled via the same two RF datapaths and antenna 304 to the antennas 306, 308, 310 and 312 of fullduplex bridges A, B, C and D. Each of these full duplex bridges iscoupled via a single Ethernet port to Ethernet networks 314, 316, 318and 320. Each of the devices on those networks 314, 316, 318 and 320 canexchange packets with any of the devices on network 300 via the fivefull duplex radio bridges of FIG. 14 as long as the antennas of the fullduplex radio bridges are within line of sight communication with antenna304. The practical limit is 124 full duplex bridges. In other words, nofull bridge can talk to more than 124 full duplex bridges at anyparticular time.

Although the invention has been described in terms of the preferred andalternative embodiments disclosed herein, those skilled in the art willappreciate still other alternative embodiments that fall within theteachings of the invention. All such alternative embodiments areintended to be included within the scope of the claims appended hereto.

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 17. An apparatus comprising: a Ethernet port having atransmit data path and a receive data path; a first radio transceiverhaving a receive data port coupled to said transmit data path of saidEthernet port and having a transmit data port; and a second radiotransceiver having a transmit data port coupled to said receive datapath of said Ethernet port and having a receive data port coupled tosaid transmit data port of said first radio transceiver.
 18. A processfor establishing an Ethernet link connection between three elements in aring structured topology of network elements comprised of any networkelement having an Ethernet port having a transmit data path and areceive data path, and a first radio transceiver having a receive dataport coupled to said transmit data path of said Ethernet port and havinga transmit data port, and a second radio transceiver having a transmitdata port coupled to said receive data path of said Ethernet port andhaving a receive data port coupled to said transmit data port of saidfirst radio transceiver, said process comprising: sending a plurality ofbase code words along said transmit data path to said receive data portof said first radio transceiver; sending a plurality of base code wordsfrom said transmit data port of said first radio transceiver to saidreceive data port of said second radio transceiver; sending a pluralityof base code words from said transmit data port of said second radiotransceiver to said receive data path of said Ethernet port of saidnetwork element; after receiving a plurality of base control words atsaid receive data path of said Ethernet port of said network element,sending a link control word along said transmit data path to saidreceive data port of said first transceiver; after receiving a pluralityof base control words at said receive data port of said firsttransceiver, sending a link control word to said receive data port ofsaid second transceiver; after receiving a plurality of base controlwords at said receive data port of said second transceiver, sending alink control word to said receive data path of said Ethernet port ofsaid network element.
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